Jet boat steering apparatus



1968 T. E. GRAVENSTRETER 3,413,950

JET BOAT STEERING APPARATUS Filed Jan. 1967 2 Sheets-Sheet 1 1N VHVI' 0R. filo/ms E. Gmvsusmsrsra Y /wm/azdaludw m I/farne 9 s Dec. 3, 1968 T. E. GRAVENSTRETER 3,413,950

JET BOAT STEERING APPARATUS Filed Jan. 3, 1967 2 Sheets-Sheet 2 mzmvmiz. Thom/is E. mvsusmsrze z/w/z 214M Mmu United States Patent 3,413,950 JET BOAT STEERING APPARATUS Thomas E. Gravenstreter, 4419 Washington Blvd., Indianapolis, Ind. 46205 Filed Jan. 3, 1967, Ser. No. 606,684 7 Claims. (Cl. 11s-12 ABSTRACT OF THE DISCLOSURE A jet boat steering device which includes in a boat rudder a pair of diverging planes fixed to one another and between which the jet stream moves. The forward edge of one plane pivots into the jet stream before the rearward edge of the other plane to provide precise steering in slight turns. The boat has two such rudders and two pumps feeding the rudders. Reverse movement is accomplished by closing off the outlets of the pumps with gates whereby the streams flow through conduits out the sides of the boat. These reverse conduits also serve the additional function of aerating the streams to reduce spray during steering.

Background of the invention Field of the inventi0n.-T his invention relates to apparatus for the steering of jet propelled watercraft.

Description of the prior art-Steering of commercially available jet boats may-be accomplished by a pair of independently mounted deflectors which are pivoted by the engagement of camming surfaces on the deflectors. The camming surfaces are provided in order to change the steering ratio at the various degrees of turn. Other possible forms of steering for jet boats involve the use of a tubular conduit or a single steering deflector to change the direction of the jet stream and to thereby steer the watercraft.

No matter what type of steering apparatus is used, it is desirable that the apparatus meet a number of criteria or avoid certain faults. First, it is desirable that when the watercraft is moving directly forwardly there be no interference of the steering apparatus with the flow of the jet stream. Second, precise direction control should be provided at low speed and throttle setting. Third, it should not be necessary to exert a great amount of force on the steering wheel or the like in order to accomplish steering or, alternatively, it should not be necessary to move the steering wheel or the like through too great a distance in order to accomplish steering. Fourth, steering should not produce an excessive amount of spray which wets occupants of the boat and bothers water skiers. The prior art steering devices mentioned above have one or more of the above faults to some degree.

Summary of the invention One embodiment of the present invention might involve a watercraft having an outlet conduit through which liquid flows in a stream to propel the watercraft. A rudder is provided which includes a pair of planes fixed relative to one another and in spaced relation. The planes are spaced on opposite sides of the path of the stream whereby the craft can move directly forwardly without the planes interfering with the passage of the stream between them. The rudder is pivotally mounted on the craft for swinging .in a horizontal direction for engaging and deflecting the stream. The planes diverge from one another from front to rear whereby swinging of the rudder causes the forward portion of one of the planes to move into the path of the stream before the rearward portion of the other plane moves into the path of the stream so that a small portion of the stream is sliced away from and deflected away 3,413,950 Patented Dec. 3, 1968 from the main portion of the stream in a relatively shallow turn.

A primary object of the present invention is to provide an improved steering apparatus for a jet boat.

Still another object of the present invention is to provide a steering apparatus which provides precise direction control at low speeds and throttle settings.

A further object of the present invention is to provide a steering apparatus which can be operated at a steering ratio which does not require excessive manual movement of the steering device and which does not require the exertion of a substantial amount of force on the steering mechanism.

Still a further object of the present invention is to provide a steering mechanism which does not produce an excessive amount of spray when the steering mechanism is in operation.

Related objects and advantages will become apparent as the description proceeds.

The full nature of the invention will be understood from the accompanying drawings and the following description and claims.

Brief description of the drawing FIG. 1 is a top plan view of a jet boat incorporating the steering apparatus of the present invention.

FIG. 2 is a horizontal section taken through a portion of the structure of FIG. 1 and along the line 22 of FIG. 6 in the direction of the arrows.

FIG. 3 is a view similar to FIG. 2 showing a different operating position of the steering apparatus.

FIG. 4 is a view similar to FIGS. 2 and 3 of a further alternative embodiment of the invention.

FIG. 5 is an enlarged vertical section taken along the line 55 of FIG. 2 in the direction of the arrows.

FIG. 6 is an enlarged vertical section taken along the line 6-6 of FIG. 1 in the direction of the arrows.

Description of the preferred embodiment Referring now more particularly to the drawing, there is illustrated a jet boat 10 which is provided with an engine 11 coupled by a universal joint 12 to a shaft 15 which is in turn coupled to a pump assembly 16 by means of universal joint 17. The pump assembly 16 which is shown and described in more detail in my copending application entitled Jet Boat Pump, Ser. No. 606,682 and filed on even date herewith is also illustrated in FIG. 6.

Briefly, the function of the pump assembly 16 is to move water into the pump assembly through inlet conduits 18 which lead into the opposite sides of the pump assembly. A pair of pumps 19 are provided each including a rotor 20 (FIG. 6) having a large plurality of radially outwardly extending wire fingers. Each rotor operates on the water to move it rotationally and centrifugally in a respective housing 21 so that it flows through a respective outlet conduit 22 leading from the housing at the rear of the boat. Because there are two such impellers 20 provided and two outlet conduits 22, two jets or water streams are created which proceed from the rear of the boat and move through respective rudders 25. The two rudders 25 are positioned symmetrically relative to the boat each being equally spaced from a longitudinal horizontal center line through the boat.

A steering wheel 26 is provided at the forward portion of the boat and is coupled to a pair of cords 27 (FIG. 6) which extend around the sides and rear of the boat. Depending upon the direction in which the steering wheel 26 is turned, the cords 27 move into the paper or out of the paper as the cords are viewed in FIG. 6. The cords 27 are fixed to a linkage 30 which is pivotally mounted within the transom 31 of the boat by means of a bearing 32. The linkage 30 consists of a lever 35 which extends through the transom and is coupled to a link member 36. The link member 36 is coupled to a further link 37 extending between the rudders 25.

Each of the rudders 25 is pivotally mounted on the watercraft for swinging about the respective axes 45 by means of oppositely projecting stub shafts 44 which are received in brackets 43 fixed to the transom 31 of the watercraft. When the steering wheel is turned, the member 35 is caused to pivot about the axis of its central portion 40, causing the link 37 to be moved transversely of the boat and causing the rudders 25 to move or pivot about axes 45, steering the boat. The link 37 is pivoted at its opposite ends to the rudders 25 and is pivotally connected between its opposite ends to the link member 36. The link member 36 is in turn pivotally connected to the member 35.

Referring now in more detail to FIGS. 2, 3 and 5, a respective one of the rudders 25 is illustrated, it being understood that the two rudders 25 are identical in configuration and operation. The rudder 25 is a hollow tube consisting of a pair of diverging planes 50 and 51 which are connected together by an upper portion 52 and a lower portion 53. The planes 50 and 51 diverge from one another from front to rear of the watercraft. Thus, when the rudder 25 is pivoted about the axis 45, the forward portion 61 of the plane 50 moves into the stream 62 before the rearward portion 63 of the plane 51 moves into the stream '62. Between these two positions there is, in one preferred embodiment, about 15 degrees of rudder turn. Contacting of the stream 62 by the forward edge 61 causes a slab of water 65 (FIG. 3) to be sliced off of the main body of the stream 62 and this slab of water to be deflected, causing a turning moment on the watercraft.

Because of the fact that the forward edge 61 of the plane 50 is forward of the axis 45, steering of the craft does not require great force. The steering pressure needed to effect a slight turn to the rudder can be adjusted by the location of the axis 45 or, in other words, by the location of the pivot point of the rudder. As the amount of turn is increased and a larger slab 65 is peeled off, the force required to turn the steering wheel does not increase because of the shorter moment arm about the axis 45. Before this moment arm shortens to zero length, however, the rearward portion 63 of the plane 51 moves into the stream. The greater the amount of water deflected by the plane 51, the greater resistance force created against additional turning of the rudder. On the other hand, the plane 50 as it continues to move a greater amount into the stream 62 tends to take away potential water to be deflected so that it does not reach the plane 51. These factors act to balance the steering to make it easy and precise throughout the steering range.

Of course, turning in the opposite direction produces the same sort of reaction with the planes 50 and 51 being reversed. In other words, the forward edge 70 of the plane 51 moves into the jet stream 62 before the rearward edge 71 of the plane 50 moves into the stream.

At low speeds the static water level is as shown at 75 in FIGS. and 6. In other words, the rudder assembly is awash so that the jet stream 62 moving at high velocity causes an induced secondary water flow from around the hull and around the rudder 25 through the biplane rudder 25. This increased mass flow of water through the rudder 25 at low velocity allows precise direction control with low throttle settings, adding a substantial increase in maneuverability over previous steering systems. It will be noted that in order to permit such aspirating or inducing of secondary water flow the forward portion of the rudder 25 is spaced away from the watercraft providing a relatively large opening 80 therebetween so that water can flow into each rudder 25.

As is described in more detail in my above mentioned copending application, the housing 21 is provided with a gate 100 which can be dropped downwardly to close off the outlet 22. When the gate is so closed, water is caused to flow through reverse conduits 101, both of which lead away from the outlet conduits 22 of pumps 19 and forwardly of the craft to exhaust at the sides 103 of the craft. These conduits 101 are left open when the gate is in the up position of FIG. 6 so that air is sucked into the water stream 62 as it moves rearwardly out of the housing 21. It has been found that the addition of this air to the water stream acts in the same fashion as the operation of a water faucet nozzle constructed to aspirate air into the water stream. In other words, the force of the air-containing water striking an object is substantially less than pure water and the blow or reaction created thereby is softened. This effect has been found to be particularly useful in the steering operation described above and illustrated in FIGS. 2- and 3. Thus, when the slab 65 of Water is sliced away from the main stream 62 of water, there is very little spray created.

Referring to FIG. 4 there is illustrated a further embodiment of the invention which is identical to the embodiment described in FIGS. l-4 and 6, with the exception that a pair of additional planes and 111 are provided on the rudder and are mounted just outside of and parallel to the planes 50 and 51. The operation of the embodiment illustrated in FIG. 4 is generally the same as the operation of the embodiment described above.

It will be evident from the above description that the resent invention provides jet boat steering apparatus which does not interfere with the jet stream when the boat is moving directly forwardly. It will also be evident that the jet steering apparatus of the present invention provides precise direction control at low speeds and throttle settings. It can also be seen that the ease of steering which is provided by the leading edges of the rudder does not permit the boat steering to run away with itself since there is an automatic correcting factor when the outside plane is engaged by the jet stream. It will also be evident from the above description that the steering apparatus of the present invention does not produce excessive spray and also does not require an excessive amount of force to effect steering. Furthermore, the steering ratio made possible by the present invention is such that the steering wheel does not need to be turned through a substantial number of turns in order to move the rudders from one end to the other of their steering adjustment.

The invention claimed is:

1. In a watercraft having an outlet conduit through which liquid flows in a stream to propel the watercraft, the improvement which comprises: a rudder including a pair of planes fixed relative to one another and in spaced relation, said rudder being spaced rearwardly of said conduit said planes being spaced on opposite sides of the path of said stream whereby said craft can move directly forwardly, said rudder being pivotally mounted on said craft for swinging in a horizontal direction, said planes diverging from one another from front to rear whereby swinging of said rudder causes the forward portion of one of said planes to move into the path of said stream before the rearward portion of the other plane moves into the path of said stream said liquid moving on both sides of said one plane when said rudder is so swung.

2. The watercraft of claim 1 wherein said rudder is a hollow tube and said planes are connected by an upper portion and a lower portion of said tube, said rudder being positioned at a sufliciently low location on said watercraft to be awash when said watercraft is stationary or is moving at low speed, said rudder being spaced a suflicient distance away from said watercraft to cause entrainment of water into said stream when said rudder is awash to facilitate steering at low speed.

3. The watercraft of claim 1 wherein said outlet conduit has an opening in the sidewall thereof and leading to atmosphere and into which air is entrained by the movement of said stream through said conduit.

4. The watercraft of claim 1 additionally comprising a second outlet conduit through which liquid flows in a second stream to propel the watercraft, said second outlet being in parallel relation to said first outlet, a second rudder including a pair of second planes fixed relative to one another and in spaced relation, said second planes being spaced on opposite sides of the path of said second stream, said second rudder being pivotally mounted on said watercraft for swinging in a horizontal direction, said second planes diverging from one another from front to rear whereby swinging of said rudder causes the forward portion of one of said second planes to move into the path of said stream before the rearward portion of the other plane moves into the path of said stream.

5. The watercraft of claim 1 wherein said planes diverge at such an angle that the rudder can be turned through 15 degrees between the contacting of the forward portion of said one plane and said stream and the rearward portion of said other plane and said stream.

References Cited UNITED STATES PATENTS 3,258,916 7/1966 Lehmann 115-42 X FOREIGN PATENTS 986,529 3/1951 France.

FERGUS S. MIDDLETON, Primary Examiner.

T. M. BLlX, Assistant Examiner. 

